Health Topics

Vision Correction Surgery

How Do Vision Correction Surgeries Work?

Vision correction surgery, also called refractive eye surgery, is any surgical procedure used to correct refractive error. In recent years, tremendous advancements have been made in this field. After refractive surgery, many patients report seeing better than they had at any other time in their lives.

All vision correction surgeries work by reshaping the front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. There are a number of different surgical procedures used to reshape the eye. The surgeon will help determine the best procedure based on eye measurements.

Vision Correction Surgical Procedures


Short for laser in-situ keratomileusis, this procedure is used to correct vision in people who are nearsighted, farsighted, and/or have astigmatism. During LASIK, vision is corrected by reshaping underlying corneal tissue so that it can properly focus light into the eye and onto the retina. This procedure is most common and is performed by creating a flap with a laser in the outer layer of the cornea to reshape the layers underneath, resulting in fast healing time with minimal discomfort.


Short for photorefractive keratectomy, this procedure is used to correct mild to moderate nearsightedness, farsightedness, and/or astigmatism. During PRK, an eye surgeon uses a laser to reshape the cornea. This laser, which delivers a cool pulsing beam of ultraviolet light, is used on the surface of the cornea not underneath the cornea, like in LASIK. Therefore, no cutting is required. Patients may experience some discomfort after surgery and healing time may be somewhat longer than LASIK.


This procedure is performed by inserting an intraocular lens, much like the ones used in cataract surgery, in front of a patients own lens, without interrupting the surface layers. This procedure is fairly new but significant advancements are continuously being made.

Are these procedures safe and effective?

While the results of corrective surgeries have been promising, there are possible side effects. It is important to keep these side effects in mind when considering vision correction surgery.

  • Infection and delayed healing: Infection resulting from PRK occurs in one-tenth of one percent of patients. For LASIK, this number is even smaller. If an infection does result from surgery, it generally means added discomfort and a longer healing process.
  • Undercorrection or overcorrection: It is difficult to accurately predict the success of eye surgery until the eye has healed properly. Patients may still need to wear corrective lenses even after surgery. Often surgeries resulting in undercorrections can be adjusted with a second surgery.
  • Worse vision: Occasionally the vision through corrective lenses is actually worse after the surgery than it was before surgery. This may be a result of irregular tissue removal or excess corneal haze.
  • Excess corneal haze: Corneal haze occurs as a part of the natural healing process after some of these procedures, including PRK. It usually has no effect on the final outcome of vision after surgery and can only be seen through an eye examination. Occasionally, however, this haze may affect a patient’s vision. A second surgery may be needed to correct it. The risk of corneal haze is much less with LASIK than it is with PRK.
  • Regression: Sometimes the effects of surgery gradually disappear over a period of several months. When this happens a second surgery is often recommended to achieve permanent results.
  • Halo effect: The halo effect is an optical effect that occurs in dim light. As the pupil enlarges, the untreated area on the outside of the cornea produces a second image. Occurring sometimes in patients having LASIK or PRK, this can affect and interfere with night driving, especially in patients who have big pupils in dark conditions.

Refractive surgeries require healthy eyes that are free from retinal problems, corneal scars, and any eye disease. Beyond side effects, there are other questions to ask before deciding on refractive surgery, such as:

  • Will your insurance cover the cost?
  • How long will recovery take?
  • Will there be any activity restrictions after surgery?

As technology progresses more and more, it is very important that you explore all options and possibilities before deciding which vision repair treatment is right for you.